Initial work on copying an ELF file

[centaur.git] / src / fixup / phdr.c

diff --git a/src/fixup/phdr.c b/src/fixup/phdr.c
new file mode 100644 (file)
index 0000000..ccdc021
--- /dev/null
+++ b/src/fixup/phdr.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+#include <libelf.h>
+#include <gelf.h>
+
+void elfu_fixupPhdrSelfRef(Elf *e)
+{
+  GElf_Ehdr ehdr;
+  size_t i, n;
+
+  if (!gelf_getehdr(e, &ehdr)) {
+    fprintf(stderr, "gelf_getehdr() failed: %s.", elf_errmsg(-1));
+    return;
+  }
+
+  if (elf_getphdrnum(e, &n)) {
+    fprintf(stderr, "elf_getphdrnum() failed: %s\n", elf_errmsg(-1));
+  }
+
+  for (i = 0; i < n; i++) {
+    GElf_Phdr phdr;
+
+    if (gelf_getphdr(e, i, &phdr) != &phdr) {
+      fprintf(stderr, "gelf_getphdr() failed for #%d: %s\n", i, elf_errmsg(-1));
+      continue;
+    }
+
+    if (phdr.p_type == PT_PHDR) {
+      phdr.p_offset = ehdr.e_phoff;
+      phdr.p_filesz = elf32_fsize(ELF_T_PHDR, n, EV_CURRENT);
+      phdr.p_memsz = phdr.p_filesz;
+
+      if (!gelf_update_phdr (e, i, &phdr)) {
+        fprintf(stderr, "gelf_update_ehdr() failed: %s\n", elf_errmsg(-1));
+      }
+    }
+  }
+
+  /* Tell libelf that phdrs have changed */
+  elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
+}